A liquid crystal display device includes a lower substrate including a color filter including a light blocking layer, a lower substrate on which an ITO pixel electrode is formed; an active circuit portion including a liquid crystal layer, a thin film transistor, and a capacitor layer; and an upper substrate on which an ITO pixel electrode is formed.
The light blocking layer blocks uncontrolled light transmitted out of a transparent pixel electrode of a substrate and thus prevents contrast reduction due to light transmitted through a thin film transistor. Red, green, and blue color layers transmit light with a predetermined wavelength of white light and display colors.
The light blocking layer is generally manufactured by a pigment dispersion method. The pigment dispersion method includes coating a transparent substrate with a colorant-containing photopolymerizable composition, exposing to provide a pattern by thermal curing, and removing non-exposed portions with a solvent.
However, when a photosensitive polyimide or phenol-based resin is used as a binder resin in the pigment dispersion method, high heat resistance may be obtained but sensitivity can be lowered and an organic solvent is required as a development solvent. A photoresist using an azide compound can have low sensitivity and heat resistance and may be affected by oxygen during exposure.
There have been attempts to improve taper characteristics by increasing the amount of a pigment in a photosensitive resin composition. There have also are been attempts to increase glass transition temperature by using a binder resin having a large molecular weight, a dispersing agent, or the like. These efforts, however, can result in deteriorating resolution or a development margin.
Accordingly, there is a need for a photosensitive resin composition that can have excellent pattern linearity, resolution, and the like as well as improved taper characteristics.